In ink jet printers that consume large amounts of ink, a stationary type of ink tank is employed. When this type of ink tank is used, the configuration of a connection body for ink supply provided on the ink jet printer side can be broadly classified into two types.
One type uses a needle-shaped body as the connection body. In this type, ink is supplied by sticking the needle-like body into a rubber seal provided in an ink supply port in the ink tank. The other type uses a tube-shaped body as the connection body. In this type, a cylindrical regulating body, which includes a valve and a spring-shaped elastic member that urges the valve toward an ink supply port, is fixed to the ink supply port in the ink tank. Ink is supplied by causing the valve to be moved against a spring force by the tube-shaped body and to open the ink supply port.
The invention described in Japanese Patent Application Laid-Open No. 2004-291246 is an example of the latter of the two types described above. In this configuration, the ink is stored in a bag-shaped ink storage body. The bag-shaped ink storage body collapses as the ink is supplied.
On the other hand, the invention described in WO2000/003877 pamphlet is another example of the latter of the two types described above. In this configuration, the ink is directly stored in a rigid housing. A printer connection body includes an ink lead-out port and an air introduction port. Air is introduced into the ink tank from the air introduction port while the ink is being supplied from the ink lead-out port.
According to a drawing illustrating an embodiment described in WO2000/003877 pamphlet (FIG. 14 attached to the present specification), in the relationship between a sealing valve 403 and a spring 404 in a connection portion between a main tank 401 and an ink tank unit 402, an opening 405 is formed above the sealing valve 403, and the position of the upper portion of the sealing valve 403 is not regulated. Therefore, there is a possibility that the position of the sealing valve 403 deviates during the opening and closing of the sealing valve 403. There is consequently the problem that it is difficult to maintain the seal properties of the connection portion between the main tank 401 and the ink tank unit 402.
In addition, if the ink tank itself is accidentally dropped, the position of the sealing valve deviates as described above, so that the problem of ink splattering onto a user or the floor can occur.
Concerning this problem, the problem can be resolved by configuring in the same manner as in a drawing illustrating an embodiment described in Japanese Patent Application Laid-Open No. 2004-291246 (FIG. 15 attached to the present specification). Specifically, the problem can be resolved by extending a connection portion 401a between the main tank 401 and the sealing valve 403 to block the opening 405 above the sealing valve 403.
In the case where the connection portion 503 illustrated in FIG. 15, which includes a sealing valve 501 and a spring 502, is applied to the exemplary configuration in the FIG. 14 like that described in WO2000/003877 pamphlet, the configuration lacks an opening above the sealing valve. Therefore, bubble releasability from the connection portion 503 deteriorates when ink supply (arrow P) is performed simultaneously with air introduction (arrow Q), so that there is a risk that the ink cannot be stably supplied to a liquid discharge recording portion.